Multilayer ceramic electronic component

ABSTRACT

There is provided a multilayer ceramic electronic component including: a lamination main body including a dielectric layer; and a plurality of inner electrode layers formed within the lamination main body and having ends exposed from one or more faces of the laminated main body, wherein when a distance between central portions of adjacent inner electrodes among the plurality of inner electrodes is T 1  and a distance between non-exposed edges of the adjacent inner electrodes is T 2 , the ratio (T 2 /T 1 ) of T 2  to T 1  is 0.80 to 0.95.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Korean Patent Application No.10-2011-0052479 filed on May 31, 2011, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multilayer ceramic electroniccomponent and, more particularly, to a multilayer ceramic electroniccomponent having excellent reliability.

2. Description of the Related Art

In general, an electronic component using a ceramic material such as acapacitor, an inductor, a piezoelectric element, a varistor, athermistor, or the like, includes a ceramic main body made of a ceramicmaterial, inner electrodes formed within the interior of the ceramicmain body, and outer electrodes installed on a surface of the ceramicmain body such that they are connected with the inner electrode.

Among ceramic electronic components, a multilayer ceramic capacitorincludes a plurality of laminated dielectric layers, inner electrodesdisposed to face each other with a dielectric layer interposedtherebetween, and outer electrodes electrically connected with the innerelectrodes.

The multilayer ceramic capacitor is commonly used as a component ofmobile communication devices such as computers, PDAs (Personal DigitalAssistants), mobile phones, and the like, due to its advantages of beingsmall, guaranteeing high capacity, and being easily mounted.

Recently, as electronic products have been reduced in size and themultifunctionality thereof has been developed, chip components have alsobecome compact and highly functional, so a multilayer ceramic capacitorproduct which is small but has high capacity is therefore in demand.

In order to increase the capacity of the multilayer ceramic capacitor,the thicknesses of a dielectric layer and the inner electrode layer arerequired to be reduced and the number of laminated layers thereof isrequired to be increased. However, as the dielectric layer and the innerelectrodes are thinned and the number of laminated layers thereofincreases, there is a high possibility of a dielectric breakdown, adelamination and cracks to thereby degrade the reliability of themultilayer ceramic capacitor. Thus, there is a limitation in reducingthe size of the multilayer ceramic capacitor and increasing the capacityof the multilayer ceramic capacitor.

SUMMARY OF THE INVENTION

An aspect of the present invention provides a multilayer ceramicelectronic component having excellent reliability.

According to an aspect of the present invention, there is provided amultilayer ceramic electronic component including: a lamination mainbody including a dielectric layer;

and a plurality of inner electrode layers formed within the laminationmain body and having ends exposed from one or more faces of thelaminated main body, wherein when a distance between central portions ofadjacent inner electrodes among the plurality of inner electrodes is T1and a distance between non-exposed edges of the adjacent innerelectrodes is T2, a ratio (T2/T1) of T2 to T1 is 0.80 to 0.95.

The distance T1 between the central portions of the adjacent innerelectrodes in a lamination direction may be less than 0.66 μm.

The distances T1 and T2 may be measured in a section perpendicular to afirst face of the lamination main body, wherein the edges of the innerelectrodes are not exposed from the first face of the lamination mainbody.

A thickness D1 of a central portion of the lamination main body isgreater than a thickness D2 of a first face of the lamination main body,wherein the edges of the inner electrodes are not exposed from the firstface of the lamination main body.

A ratio of the thickness D2 of the first face of the lamination mainbody to the thickness D1 of the central portion of the lamination mainbody may be 0.78 to 0.95.

The thickness of the central portion of the lamination main body may bemeasured at a capacity formation portion in which the plurality of innerelectrodes overlap each other.

The thickness D1 of the central portion of the lamination main body mayrange from 200 μm to 300 μm.

A thickness D1 of a central portion of the lamination main body may begreater than a thickness D3 of a second of the lamination main body,wherein the ends of the inner electrodes are exposed from the secondface of the lamination main body.

A ratio of the thickness D3 of the second face of the lamination mainbody to the thickness D1 of the central portion of the lamination mainbody may be 0.75 to 0.97.

The thickness D3 of the second face of the lamination main body may bemeasured at an area of the lamination main body in which the innerelectrodes are present.

A thickness of one of the inner electrode layers may be 0.7 μm or less.

According to another aspect of the present invention, there is provideda multilayer ceramic capacitor including: a lamination main body havingfirst and second faces; and a plurality of inner electrode layers formedwithin the lamination main body and having ends exposed from the firstand second faces, respectively, wherein when a distance between centralportions of adjacent inner electrodes among the plurality of innerelectrodes is T1 and a distance between non-exposed edges of theadjacent inner electrodes in a lamination direction is T2, a ratio(T2/T1) of T2 to T1 is 0.80 to 0.95, and the distance between thecentral portions of the adjacent inner electrodes is less than 0.66 μM.

The first and second faces may oppose each other and be disposed in alengthwise direction of the lamination main body.

A thickness D1 of a central portion of the lamination main body may begreater than a thickness D2 of a third face of the lamination main body,wherein the edges of the inner electrodes are not exposed from the thirdface.

A ratio of the thickness D2 of the third face of the lamination mainbody to the thickness D1 of the central portion of the lamination mainbody may be 0.78 to 0.95. A ratio of the thickness D3 of one of thefirst and the second faces of the lamination main body to the thicknessD1 of a central portion of the lamination main body may be 0.75 to 0.97.

According to another aspect of the present invention, there is provideda multilayer ceramic capacitor including: a lamination main body; aplurality of first and second inner electrode layers formed within thelamination main body and having ends exposed from one of end faces ofthe lamination main body in a lengthwise direction, respectively; and adielectric layer disposed between the first and second inner electrodelayers and having a thickness less than 0.66 μM, wherein a thickness D1of a central portion of the lamination main body is greater than athickness D2 of an edge portion of the lamination main body in awidthwise direction, and when a distance between adjacent innerelectrodes in the central portion of the lamination main body is T1 anda distance between the adjacent inner electrodes at the edges of theinner electrodes in the widthwise direction is T2, a ratio (T2/T1) of T2to T1 is 0.80 to 0.95.

A ratio of the thickness D2 of the edge portion of the lamination mainbody in the widthwise direction to the thickness D1 of the centralportion of the lamination main body may be 0.78 to 0.95.

The thickness D1 of the central portion of the lamination main body maybe greater than a thickness D3 of the end faces of the lamination mainbody in the lengthwise direction.

A ratio of the thickness D3 of the end faces of the lamination main bodyin the lengthwise direction to the thickness D1 of the central portionof the lamination main body may be 0.75 to 0.97.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a schematic perspective view of a multilayer ceramic capacitoraccording to an embodiment of the present invention;

FIG. 2 is a schematic exploded perspective view of a lamination mainbody according to an embodiment of the present invention;

FIG. 3 is a cross-sectional view taken along line A-A′ in FIG. 1;

FIG. 4 is a cross-sectional view taken along line B-B′ in FIG. 1;

FIG. 5 is an enlarged sectional view of a portion of a section in awidthwise direction of the multilayer ceramic capacitor; and

FIG. 6 is an enlarged sectional view of a portion of a section of amultilayer ceramic capacitor according to another embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of the present invention will now be described in detailwith reference to the accompanying drawings. The invention may, however,be embodied in many different forms and should not be construed as beinglimited to the embodiments set forth herein. Rather, these embodimentsare provided so that this disclosure will be thorough and complete, andwill fully convey the scope of the invention to those skilled in theart. In the drawings, the shapes and dimensions may be exaggerated forclarity, and the same reference numerals will be used throughout todesignate the same or like components.

FIG. 1 is a schematic perspective view of a multilayer ceramic capacitoraccording to an embodiment of the present invention, and FIG. 2 is aschematic exploded perspective view of a lamination main body. FIG. 3 isa cross-sectional view taken along line A-A′ in FIG. 1, namely, across-sectional view taken in a widthwise direction (or in a Wdirection) of the multilayer ceramic capacitor. FIG. 4 is across-sectional view taken along line B-B′ in FIG. 1, namely, across-sectional view taken in a lengthwise direction (or in an Ldirection) of the multilayered ceramic capacitor. FIG. 5 is an enlargedsectional view of a portion of a section in a widthwise direction of themultilayer ceramic capacitor.

In the present embodiment, it may be defined such that the ‘lengthwisedirection’ of the multilayer ceramic capacitor is the ‘L’ direction, the‘widthwise direction’ is the ‘W’ direction, a ‘thicknesswise direction’is the ‘T’ direction (or a vertical direction) in FIG. 1. The‘thicknesswise direction’ may have the same concept as a ‘laminationdirection’ in which dielectric layers are laminated.

With reference to FIGS. 1 through 5, the multilayer ceramic capacitoraccording to an embodiment of the present invention may include alamination main body 110, and outer electrodes 131 and 132 formed atboth end portions of the lamination main body.

As shown in FIG. 2, the lamination main body 110 may be formed bylaminating a plurality of dielectric layers 111 in the thicknesswisedirection. The plurality of dielectric layers constituting thelamination main body 110 are in a sintered state to be integrated suchthat the boundary between adjacent dielectric layers cannot easily bediscerned.

The dielectric layers may be made of ceramic powder having highpermittivity. For example, a barium titanate (BaTiO₃)-based powder, astrontium titanate (SrTiO₃)-based powder, or the like, may be used, butthe present invention is not limited thereto. The thickness of onedielectric layer 111 may be less than 0.66 μm, but the present inventionis not limited thereto. Alternatively, the thickness of one dielectriclayer 111 may be 0.4 μm or greater but less than 0.66 μm. Alternatively,the thickness of one dielectric layer 111 may range from 0.45 μm to 0.55μm.

In an embodiment of the present invention, the thickness of onedielectric layer 111 may refer to an average thickness of one dielectriclayer 111 disposed between the inner electrode layers 121 and 122. Theaverage thickness of the dielectric layer may be measured by scanning animage of a section in the lengthwise direction of the lamination mainbody 110 as shown in FIG. 4 by using a scanning electron microscope(SEM) of 10,000 magnifications. In detail, the thickness of onedielectric layer 111 may be measured at 30 points at equal intervals inthe lengthwise direction in the scanned image, to thus measure theaverage thickness value thereof. The 30 points at equal intervals may bedesignated at a capacity formation portion E. As shown in FIG. 4, thecapacity formation portion E may refer to an area in which the first andsecond inner electrodes 121 and 122 overlap each other. Also, such anaverage value measurement may extend to be performed at 10 dielectriclayers to measure an average value, whereby an average thickness of thedielectric layers can be further generalized.

Also, the thickness of one dielectric layer may be defined as an averagedistance between the central portions of the mutually adjacent innerelectrode layers 121 and 122. For example, the distances betweenmutually adjacent inner electrode layers may be measured at 30 points atequal intervals in the lengthwise direction of the inner electrodelayers may be measured on the scanned image to calculate an averagedistance. Also, the average distance between mutually adjacent innerelectrode layers may extend to ten pairs of inner electrode layersdisposed at the capacity formation portion E to measure an averagedistance, whereby the average distance between mutually adjacent innerelectrode layers can be further generalized.

The distance between the central portions of the mutually adjacent firstinner electrode layer 121 and the second inner electrode layer 122 maybe less than 0.66 μm, but the present invention is not limited thereto.Alternatively, the distance between the central portions of the mutuallyadjacent first and second inner electrode layers 121 and 122 may be 0.4μm or greater but less than 0.66 μm. Alternatively, the distance betweenthe central portions of the mutually adjacent first and second innerelectrode layers 121 and 122 may range from 0.45 μm to 0.55 μm.

A plurality of inner electrodes 121 and 122 may be formed in theinterior of the lamination main body 110. The inner electrodes 121 and122 are formed on the dielectric layers 111 and may be disposed suchthat the inner electrodes 121 and 122 face each other with onedielectric layer interposed therebetween in the lamination direction ofthe dielectric layers through sintering. The inner electrode layers maybe made of a conductive metal such as nickel (Ni), copper (Cu),palladium (Pd), or the like, and the thickness of one inner electrodelayer may be 0.7 μm or less, but the present invention is not limitedthereto

According to an embodiment of the present invention, more than twohundred dielectric layers, on which the inner electrode layers arerespectively formed, may be laminated.

As for the plurality of inner electrodes 121 and 122, the first andsecond inner electrodes 121 and 122, having different polarities, may bepaired.

A lengthwise directional marginal portion L1, in which the first innerelectrode 121 or the second inner electrode 122 are not formed, may beformed in the lengthwise direction L of the lamination main body 110,and widthwise directional marginal portions W1 and W2, in which thefirst inner electrode 121 and the second inner electrode 122 are notformed, may be formed in the widthwise direction W of the laminationmain body 110.

One end of each of the first and second inner electrodes 121 and 122 isspaced apart from one end face of the lamination main body by thepresence of the lengthwise directional marginal portion L1, and theother end of each of the first and second inner electrodes 121 and 122may be exposed from one end face of the lamination main body.

The ends of the first and second inner electrodes 121 and 122 exposedrespectively from both end faces of the lamination main body 110 may berespectively electrically connected with the first and second outerelectrodes 131 and 132 formed on both end faces of the lamination mainbody.

Capacitance may be formed in an area of the lamination main body 100, inwhich the first and second inner electrodes 121 and 122 overlap eachother, when an electric field is applied thereto. In an embodiment ofthe present invention, the area in which the first and second innerelectrodes 121 and 122 overlap each other will be referred to as thecapacity formation portion E. Also, an area of the lamination main body,in which the first and second inner electrodes do not overlap each otherand only the first inner electrode or the second inner electrode isformed, will be referred to as an electrode draw-out portion. Theelectrode draw-out portion may be formed by the lengthwise directionalmarginal portion L1. According to an embodiment of the presentinvention, the first inner electrode or the second inner electrode maybe exposed to one end of the lamination main body through the electrodedraw-out portion.

According to an embodiment of the present invention, the end of each ofthe inner electrodes may be exposed from one or more faces of thelamination main body, but the present invention is not limited thereto.

Although not shown, the first or second inner electrodes may be exposedfrom the same face of the lamination main body. Alternatively, the endsof the first or second inner electrodes may be exposed from two or morefaces of the lamination main body by two or more electrode draw-outportions.

According to an embodiment of the present invention, the thickness ofthe central portion of the lamination main body may be greater than thatof one face, of the lamination main body, from which the ends of theinner electrodes are not drawn out.

As shown in FIG. 3, according to an embodiment of the present invention,the thickness D1 of the central portion of the lamination main body maybe greater than the thickness D2 of the edge portion of the laminationmain body in the widthwise direction. The thickness D1 of the centralportion of the lamination main body may be measured at the capacityformation portion E in which the first and second inner electrodes 121and 122 overlap each other to form capacitance. Also, the thickness D1of the central portion of the lamination main body may be a maximumthickness of the lamination main body. The thickness D2 of the edgeportion of the lamination main body in the widthwise direction may bemeasured at the widthwise directional marginal portions W1 and W2 inwhich the inner electrodes are not formed.

There is a difference in density between the capacity formation portionE of the lamination main body in which the first and second innerelectrodes overlap each other and the marginal portions in which thefirst inner electrode or the second inner electrode is not formed. Whenthe difference in density between the capacity formation portion E andthe marginal portions is increased, the marginal portion may bedelaminated or cracked. Then, a plating solution may infiltrate into thedelaminated or cracked portion, resulting in a degradation of thereliability of the multilayer ceramic capacitor.

According to an embodiment of the present invention, the capacityformation portion E and the widthwise directional marginal portions W1and W2 are differentially compressed to reduce the difference indensity. A delamination or cracking incidence of the multilayer ceramiccapacitor can be lowered and dielectric breakdown voltagecharacteristics can be improved by adjusting the ratio of thethicknesses of the capacity formation portion E and the widthwisedirectional marginal portions W1 and W2.

According to an embodiment of the present invention, the ratio (D2/D1)of the thickness of the edge portion of the lamination main body to thethickness of the central portion of the lamination main body may be 0.78to 0.95. The thickness D1 of the central portion of the lamination mainbody may range from 250 μm to 350 μm, but the present invention is notlimited thereto. Alternatively, the thickness D1 of the central portionof the lamination main body may range from 310 μm to 320 μm.

If the ratio of D2 to D1 is less than 0.78, the edges of each of theinner electrodes in the widthwise direction would be overly bent tosignificantly reduce the interval between the vertically adjacent innerelectrodes compared with the central portion. Then, an electric fieldwould be concentrated in the edges of each of the inner electrodes inthe widthwise direction to degrade the dielectric breakdown voltagecharacteristics, degrade the characteristics under a high temperaturecondition and a moisture resistance condition, and degrade an averagelife span.

Also, if the ratio of D2 to D1 exceeds 0.95, there would be highpossibility of the generation of a delamination or cracks, and thecracks would possibly degrade dielectric breakdown voltagecharacteristics as well as high temperature and moisture resistancecharacteristics.

FIG. 5 is an enlarged sectional view of a portion of a section in awidthwise direction of the multilayer ceramic capacitor. FIG. 5 may showa section perpendicular with respect to one face, of the lamination mainbody, from which the edges of inner electrodes are not exposed. FIG. 5may be a sectional view taken along a line across the central portion ofthe lamination main body. The non-exposed edges of the inner electrodesformed in the lamination main body can be understood with reference toFIG. 5.

With reference to FIG. 5, according to an embodiment of the presentinvention, the distance between vertically adjacent inner electrodes inthe central portion of the lamination main body may be greater than thedistance between vertically adjacent inner electrodes at the edges ofthe inner electrodes in the widthwise direction.

The distance between the vertically adjacent inner electrodes 121 and122 in the central portion of the lamination main body may be defined asT1. The central portion of the lamination main body may refer to an areain which the edges of the inner electrodes in the widthwise directionare not bent.

Also, the distance between the vertically adjacent inner electrodes 121and 122 at the edges of the inner electrodes in the widthwise directionmay be defined as T2. The edges of the inner electrodes in the widthwisedirection may include an oxidized area of the inner electrodes.

The ratio (T2/T1) of T2 to T1 may be 0.80 to 0.95. The distance T1between the vertically adjacent inner electrodes 121 and 122 in thecentral portion of the lamination main body may be less than 0.66 μm,but the present invention is not limited thereto.

If the ratio (T2/T1) of T2 to T1 is less than 0.80, the widthwisedirectional marginal portions W1 and W2 would possibly be overlycompressed, and the edges of the inner electrodes in the widthwisedirection would possibly be overly bent. Then, the distance between theedges of the vertically adjacent inner electrodes in the widthwisedirection would be shortened, making the dielectric layer positionedtherebetween thinner, to causing an electric field to be concentratedtherein. Then, the dielectric breakdown voltage would possibly belowered and high temperature and moisture resistance characteristicswould be degraded.

Also, if the ratio (T2/T1) of T2 to T1 exceeds 0.95, the degree ofcompression of the widthwise directional marginal portions W1 and W2 isso low as to cause a delamination and cracking, the dielectric breakdownvoltage would possibly be lowered due to cracking, and the hightemperature and moisture resistance characteristics would be degraded.

FIG. 6 is an enlarged sectional view of a portion of a section of amultilayer ceramic capacitor according to another embodiment of thepresent invention. With reference to FIG. 6, similar to that of FIG. 5,depicted is a section perpendicular to one face from which the edges ofthe inner electrode of the lamination main body are not exposed. Namely,FIG. 6 illustrates the non-exposed edges of the inner electrodes formedin the lamination main body.

With reference to FIG. 6, according to an embodiment of the presentinvention, the distance T1 between the central portions of thevertically adjacent inner electrodes 121 and 122 may be longer than thedistance T2 between the edges of the vertically adjacent innerelectrodes. The central portion of the lamination main body may refer toan area in which the edges of the inner electrodes in the widthwisedirection are not bent. The edges of the inner electrodes are portionsnot exposed from the lamination main body. The edges of the innerelectrodes in the widthwise direction may include an oxidized area ofthe inner electrodes.

According to an embodiment of the present invention, in the sectionalview showing the edges of the inner electrodes not exposed from one faceof the lamination main body, the end portions of the inner electrodesmay not be arranged on a straight line. For example, as shown in FIG. 6,based on a straight line virtually drawn in the lamination direction,the edge of one inner electrode 122 may be shifted to the right, and theedge of one inner electrode may be shifted to the left. Also, in thesectional view, the lengths of the inner electrodes may not be uniform.

According to an embodiment of the present invention, as shown in FIG. 6,the distance T2 between the edges of the vertically adjacent innerelectrodes may be defined as the shortest distance from the edge of anon-protruded inner electrode to an adjacent inner electrode, based on avertical line virtually drawn in the lamination direction from the edgeof one inner electrode among vertically adjacent inner electrodes. Thevirtual vertical line may be drawn from an edge of one of two innerelectrodes as a measurement target. The shortest distance may be alength of the vertical line drawn from the edge of the non-protrudedinner electrode to its adjacent inner electrode.

The ratio (T2/T1) of T2 to T1 may be 0.80 to 0.95. The distance T1between the vertically adjacent inner electrodes 121 and 122 in thecentral portion of the lamination main body may be less than 0.66 μm,but the present invention is not limited thereto.

As described above, in order to reduce the size and increase thecapacity of the multilayer ceramic capacitor, the thicknesses of thedielectric layers and the inner electrode layers are required to bereduced and the number of laminated layers thereof is required to beincreased. However, if the dielectric layers and the inner electrodelayers are thinned and the number of laminated layers is increased, thedifference in density between the capacity formation portion in whichthe inner electrodes overlap each other and the marginal portions inwhich the inner electrodes are not formed would be increased. Then, theelectrode draw-out portion might be delaminated or cracked.

Also, if the marginal portions are overly compressed to increase thedensity of the marginal portions, the edges of the inner electrodeswould be overly bent to shorten the distance between the adjacent innerelectrodes. When the dielectric layers have a predetermined thickness,even in the case that the distance between the inner electrodes isshortened, the possibility of dielectric breakdown is low, but as thedielectric layers are thinned, the possibility of dielectric breakdownmay be increased. Namely, as the dielectric layers are thinned, theinterval between the inner electrodes becomes too narrow, increasing thepossibility of dielectric breakdown even at a low voltage.

However, according to the embodiment of the present invention, thethickness of one dielectric layer may be less than 0.66 μm and thethickness of one inner electrode layer may be 0.7 μm or less. Also, twohundred or more of the dielectric layers, on which the inner electrodelayers are formed, may be laminated.

As described above, according to the embodiment of the presentinvention, although the dielectric layers and the inner electrode layersare thinned, the concentration of an electric field in a particular areacan be prevented by adjusting the compression ratio between the capacityformation portion and the marginal portions, and the possibility ofdelamination and crack generation can be reduced.

According to the embodiment of the present invention, the thickness ofthe central portion of the lamination main body may be greater than thethickness of one face of the lamination main body to which the end ofthe inner electrode is drawn out.

As shown in FIG. 4, according to the embodiment of the presentinvention, the thickness D1 of the central portion of the laminationmain body may be greater than the thickness D3 of the end face of thelamination main body. The thickness D1 of the central portion of thelamination main body may be measured at the capacity formation portionE. Also, the end face of the lamination main body may refer to a facefrom which the end of the first inner electrode 121 or the second innerelectrode 122 is exposed in the lengthwise direction, which may be anend face formed in the lengthwise direction of the lamination main body.The thickness D3 of the end face of the lamination main body may bemeasured at the area in which the first inner electrodes 121 or thesecond inner electrodes 122 are present.

As shown in FIG. 3, the widthwise directional marginal portions W1 andW2 in which the first inner electrodes 121 and the second innerelectrodes 122 are not formed are disposed in the widthwise direction ofthe lamination main body, and the thickness D3 of the end face of thelamination main body may be the thickness of the area in which the firstinner electrodes 121 or the second inner electrodes 122 are present,rather than the widthwise directional marginal portions W1 and W2.

As described above, there may be a difference in density between thecapacity formation portion and the marginal portion, and in this case,the difference in density may be adjusted by differentially compressingthe capacity formation portion and the lengthwise directional marginalportion. The incidence of delamination or cracks in the multilayerceramic capacitor can be lowered and dielectric breakdown voltagecharacteristics can be improved by adjusting the ratio of the thicknessbetween the capacity formation portion and the marginal portion.

The ratio (D3/D1) of the thickness of the end face of the laminationmain body to that of the central portion of the lamination main body maybe 0.75 to 0.97.

If the ratio (D3/D1) of the thickness of the end face of the laminationmain body to that of the central portion of the lamination main body isless than 0.75, an electric field would possibly be concentrated in theends of the inner electrodes in the lengthwise direction to degrade thedielectric breakdown voltage characteristics as well as high temperatureand moisture resistance characteristics, although the possibility of thegeneration of delamination and cracking in the marginal portion is low.

Also, if the ratio (D3/D1) of the thickness of the end face of thelamination main body to that of the central portion of the laminationmain body exceeds 0.97, there would be high possibility that themarginal portion would be delaminated or cracked and hightemperature andmoisture resistance characteristics would possibly be degraded.

A method of manufacturing a multilayer ceramic capacitor (MLCC)according to an embodiment of the present invention will now bedescribed.

First, inner electrode patterns may be formed on a plurality of ceramicgreen sheets. The ceramic green sheets may be formed of ceramic pasteincluding ceramic powder, an organic solvent, and an organic binder.

The ceramic power having a high permeability, may include a bariumtitanate (BaTiO₃)-based material, strontium titanate (SrTiO₃)-basedmaterial, or the like, but the present invention is not limited thereto.When the ceramic green sheets are fired, dielectric layers constitutingthe lamination main body can be obtained.

The inner electrode patterns may be formed of an inner electrode pasteincluding conductive metal. The conductive metal may be nickel (Ni),copper (Cu), palladium (Pd), or an alloy thereof, but the presentinvention is not limited thereto.

A method of forming the inner electrode patterns on the ceramic greensheets is not particularly limited. For example, the inner electrodepatterns may be formed by a printing method such as a screen printingmethod, a gravure printing method, or the like.

A ceramic green sheet lamination may be formed by laminating the ceramicgreen sheets such that the inner electrode patterns formed on theindividual ceramic green sheets are exposed from different end faces bya follow-up cutting process. A thickness ratio of the lamination mainbody can be adjusted by compressing the ceramic green sheet lamination.As described above, according to an embodiment of the present invention,the marginal portion may be intensively compressed as compared with thecapacity formation portion. Also, the end faces and edge portions of thelamination main body may be intensively compressed as compared with thecentral portion of the lamination main body.

The compression may be performed with a certain pressure. Thecompression may be performed by isostatic pressing, but the presentinvention is not limited thereto. The compression may be performed underpressure conditions of 500 kgf/cm² to 1,500 kgf/cm², but the presentinvention is not limited thereto. In order to differentially compressthe capacity formation portion and the electrode draw-out portion of thelamination main body during the isostatic pressing, a subsidiarymaterial may be applied to upper and lower surfaces of the ceramic greensheet lamination. A polyethyleneterephtalate (PET) film, a vinyl film,rubber, or the like, may be used as the subsidiary material, but thepresent invention is not limited thereto.

Also, the compression may be performed at a certain temperature. Thecompression may be performed at 50□ to 100□, but the present inventionis not limited thereto.

The ceramic green sheet lamination may be cut to expose the ends of theinner electrodes in the lengthwise direction from the end faces thereof,thereby forming a ceramic green chip. The ceramic green chip may beplasticized and fired to form a lamination main body.

The plasticization process may be performed for de-binderizing, and itmay be performed under an air atmosphere, but the present invention isnot limited thereto.

The firing process may be performed under a reduction atmosphere suchthat the inner electrodes may not be oxidized.

The firing process may be performed at a temperature ranging from 900□to 1,300□.

Then, outer electrodes may be formed to be electrically connected withthe ends of the inner electrodes exposed from the end faces of thelamination main body. Thereafter, the surface of the external electrodesmay be plated with nickel, tin, or the like.

The present invention will be described in more detail with reference toexamples and comparative examples, but this is to help understand thepresent invention properly and the scope of the invention is not limitedby these examples.

EXAMPLE

Ceramic green sheets, having a thickness of 0.90 μm, 1.00 μm, and 1.25μm, respectively, were prepared. Inner electrode paste was printed oneach of the ceramic green sheets, and two hundred ceramic green sheetswere laminated to manufacture a ceramic lamination. The ceramiclamination was subjected to isostatic pressing under pressure conditionsof 500 kgf/cm2, 800 kgf/cm2 and 1000 kgf/cm2, at 85□, respectively. Inthis case, the ceramic lamination was compressed such that the centralportion of the lamination main body was larger than edge portions of thelamination main body in the widthwise direction.

The compression-completed ceramic lamination was cut in the form ofindividual chips. The separated individual chips were maintained underan air atmosphere at 230 L for 60 hours to perform de-binderizing.Thereafter, the individual chips were fired at 1, 200 L under an oxygenpartial pressure of 10⁻¹¹ atm˜10⁻¹⁰ atm, lower than a Ni/NiO equilibriumoxygen partial pressure, in a reduction atmosphere such that the innerelectrodes were not oxidized. After the firing operation, an averagethickness of the inner electrode layers was 0.65 μm. The size of thefired chips satisfied 0.6±0.09 mm×0.3±0.09 mm×0.3±0.09 mm (L×W×T). Here,T is the thickness of the central portion of the lamination main body.

The characteristics of the fired chips were evaluated and Table 1 belowshows the corresponding results.

Sections of hundreds of fired chips were inspected, and the incidence ofdelamination and cracking of the fired chips was expressed bypercentage.

Dielectric breakdown voltage (BDV) characteristics were evaluated byapplying a DC voltage at a rate of 10 V/sec, and an average life span ofthe fired chips was determined as a duration of time until insulationresistance was dropped to below 10⁴Ω.

TABLE 1 Delamination/ Average Thickness of Lamination crack life ceramicPressure Tl T2 incidence Span green sheet (kgf/cm²) (μm) (μm) T2/T1 (%)BDV(V) (hr) Comparative 1.25 500 0.69 0.65 0.94 0 83 115 example 1Comparative 1.25 800 0.69 0.60 0.87 0 80 108 example 2 Comparative 1.251000 0.67 0.55 0.82 0 81 109 example 3 Comparative 1.25 1200 0.66 0.510.77 0 78 110 example 4 Comparative 1.00 500 0.55 0.53 0.96 17 73 35example 5 Example 1 1.00 800 0.53 0.48 0.91 0 71 95 Example 2 1.00 10000.51 0.42 0.82 0 69 93 Comparative 1.00 1200 0.49 0.36 0.73 0 30 28example 6 Comparative 0.90 500 0.50 0.49 0.98 22 68 27 example 7 Example3 0.90 800 0.49 0.46 0.94 0 65 90 Example 4 0.90 1000 0.47 0.40 0.85 063 91 Comparative 0.90 1200 0.45 0.34 0.76 0 28 19 example 8

Here, T1 is the distance between the central portions of verticallyadjacent inner electrodes, and T2 is the distance between thenon-exposed edges of the vertically adjacent inner electrodes. In thisembodiment, a measurement was made in the widthwise directional sectionobtained by cutting the central portion of the lamination main body, asshown in FIG. 3.

In detail, an image of the widthwise directional section obtained bycutting the central portion of the lamination main body of each samplewas scanned by a scanning electron microscope (SEM) of 10,000magnifications. Ten pairs of adjacent inner electrodes were randomlyextracted from the scanned images, the distance T1 between the centralportions of the vertically adjacent inner electrodes and the distance T2between the edges of the vertically adjacent inner electrodes in thewidthwise direction were measured, and average measurement values areshown in Table 1.

With reference to Table 1, in comparative examples 1 through 4 in whichthe thickness of the dielectric layers after firing was 0.60 μm orgreater, no delamination or cracking was generated, irrespective of theratio of T1 and T2 and a high DVB and an excellent accelerated life spanwere achieved.

However, in comparative examples 5 and 7, the compression rate of themarginal portion was low, and the ratio of T2 to T1 was high. Thus, adelamination/cracking incidence was high and an average life span wasdegraded. Also, in comparative examples 6 and 8, the comparison ratio ofthe marginal portion was high, and delamination/cracking was notgenerated because the ratio of T2 to T1 was low, but the BDVcharacteristics were degraded due to excessive compression, and anaverage life span was degraded.

This is because the edges of the inner electrodes in the widthwisedirection were overly bent, shortening the distance between the edges ofthe inner electrodes in the widthwise direction, so an electric fieldwas concentrated therein.

In examples 1 through 4, no delamination/cracking was generated and theBDV characteristics and an average life span were excellent.

As set forth above, according to the embodiments of the presentinvention, the capacity formation portion and the widthwise directionalmarginal portion are differentially compressed to reduce a difference indensity. The incidence of delamination or cracking in the multilayerceramic capacitor is lowered by adjusting the thickness ratio betweenthe capacity formation portion and the marginal portion, and thedielectric breakdown voltage characteristics can be improved.

According to the embodiments of the present invention, the distancebetween vertically adjacent inner electrodes at the central portion ofthe lamination main body is longer than the distance between verticallyadjacent inner electrodes at the edges of the inner electrodes in thewidthwise direction. The distance between the vertically adjacent innerelectrodes at the edges of the inner electrodes in the widthwisedirection can be adjusted to prevent an electric field from beingconcentrated in the edges of the inner electrodes. Accordingly, thepossibility of the generation of delamination or cracking in themarginal portion can be reduced, and high temperature and moistureresistance characteristics and an average life span can be improved.

According to the embodiments of the present invention, the ratio betweenthe thickness of the central portion of the lamination main body andthat of the end face of the lamination main body can be adjusted toprevent an electric field from being concentrated in the ends of theinner electrodes in the lengthwise direction, whereby the possibility ofthe generation of delamination or cracking can be lowered, and thedielectric breakdown voltage characteristics can be enhanced.

According to the embodiments of the present invention, although thedielectric layers and the inner electrode layers are thinned, theconcentration of an electric field in a particular area can be preventedby adjusting the compression ratio between the capacity formationportion and the marginal portion. Thus, the possibility of thegeneration of delamination or cracking can be lowered, and thedielectric breakdown voltage characteristics and high temperature andmoisture resistance characteristics can be improved.

While the present invention has been shown and described in connectionwith the embodiments, it will be apparent to those skilled in the artthat modifications and variations can be made without departing from thespirit and scope of the invention as defined by the appended claims.

1. A multilayer ceramic electronic component comprising: a laminationmain body including a dielectric layer; and a plurality of innerelectrode layers formed within the lamination main body and having endsexposed from one or more faces of the laminated main body, wherein whena distance between central portions of adjacent inner electrodes amongthe plurality of inner electrodes is T1 and a distance betweennon-exposed edges of the adjacent inner electrodes is T2, a ratio(T2/T1) of T2 to T1 is 0.80 to 0.95.
 2. The multilayer ceramicelectronic component of claim 1, wherein the distance T1 between thecentral portions of the adjacent inner electrodes in a laminationdirection is less than 0.66 μm.
 3. The multilayer ceramic electroniccomponent of claim 1, wherein the distances T1 and T2 are measured in asection perpendicular to a first face of the lamination main body, theedges of the inner electrodes being not exposed from the first face ofthe lamination main body.
 4. The multilayer ceramic electronic componentof claim 1, wherein a thickness D1 of a central portion of thelamination main body is greater than a thickness D2 of a first face ofthe lamination main body, the edges of the inner electrodes being notexposed from the first face of the lamination main body.
 5. Themultilayer ceramic electronic component of claim 4, wherein a ratio ofthe thickness D2 of the first face of the lamination main body to thethickness D1 of the central portion of the lamination main body is 0.78to 0.95.
 6. The multilayer ceramic electronic component of claim 4,wherein the thickness D1 of the central portion of the lamination mainbody is measured at a capacity formation portion in which the pluralityof inner electrodes overlap each other.
 7. The multilayer ceramicelectronic component of claim 4, wherein the thickness D1 of the centralportion of the lamination main body ranges from 200 μm to 300 μm.
 8. Themultilayer ceramic electronic component of claim 1, wherein a thicknessD1 of a central portion of the lamination main body is greater than athickness D3 of a second face of the lamination main body, the ends ofthe inner electrodes being exposed from the second face of thelamination main body.
 9. The multilayer ceramic electronic component ofclaim 8, wherein a ratio of the thickness D3 of the second face of thelamination main body to the thickness D1 of the central portion of thelamination main body is 0.75 to 0.97.
 10. The multilayer ceramicelectronic component of claim 9, wherein the thickness D3 of the secondface of the lamination main body is measured at an area of thelamination main body in which the inner electrodes are present.
 11. Themultilayer ceramic electronic component of claim 1, wherein a thicknessof one of the inner electrode layers is 0.7 μm or less.
 12. A multilayerceramic capacitor comprising: a lamination main body having first andsecond faces; and a plurality of inner electrode layers formed withinthe lamination main body and having ends exposed from the first andsecond faces, respectively, wherein when a distance between centralportions of adjacent inner electrodes among the plurality of innerelectrodes is T1 and a distance between non-exposed edges of theadjacent inner electrodes in a lamination direction is T2, a ratio(T2/T1) of T2 to T1 is 0.80 to 0.95, and the distance between thecentral portions of the adjacent inner electrodes is less than 0.66 μm.13. The multilayer ceramic capacitor of claim 12, wherein the first andsecond faces oppose each other and are disposed in a lengthwisedirection of the lamination main body.
 14. The multilayer ceramiccapacitor of claim 12, wherein a thickness D1 of a central portion ofthe lamination main body is greater than a thickness D2 of a third faceof the lamination main body, the edges of the inner electrodes being notexposed from the third face.
 15. The multilayer ceramic capacitor ofclaim 14, wherein a ratio of the thickness D2 of the third face of thelamination main body to the thickness D1 of the central portion of thelamination main body is 0.78 to 0.95.
 16. The multilayer ceramicelectronic component of claim 12, wherein a ratio of the thickness D3 ofone of the first and the second faces of the lamination main body to thethickness D1 of a central portion of the lamination main body is 0.75 to0.97.
 17. A multilayer ceramic capacitor comprising: a lamination mainbody; a plurality of first and second inner electrode layers formedwithin the lamination main body and having ends exposed from one of endfaces of the lamination main body in a lengthwise direction,respectively; and a dielectric layer disposed between the first andsecond inner electrode layers and having a thickness less than 0.66 μm,wherein a thickness D1 of a central portion of the lamination main bodyis greater than a thickness D2 of an edge portion of the lamination mainbody in a widthwise direction, and when a distance between adjacentinner electrodes in the central portion of the lamination main body isT1 and a distance between the adjacent inner electrodes at the edges ofthe inner electrodes in the widthwise direction is T2, a ratio (T2/T1)of T2 to T1 is 0.80 to 0.95.
 18. The multilayer ceramic capacitor ofclaim 17, wherein a ratio of the thickness D2 of the edge portion of thelamination main body in the widthwise direction to the thickness D1 ofthe central portion of the lamination main body is 0.78 to 0.95.
 19. Themultilayer ceramic capacitor of claim 17, wherein the thickness D1 ofthe central portion of the lamination main body is greater than athickness D3 of the end faces of the lamination main body in thelengthwise direction.
 20. The multilayer ceramic capacitor of claim 19,wherein a ratio of the thickness D3 of the end faces of the laminationmain body in the lengthwise direction to the thickness D1 of the centralportion of the lamination main body is 0.75 to 0.97.